In recent years, a wearable motion supporting device has been put to practical use, which is worn on a body of an elderly person or a physically handicapped person, and assists and substitutes for muscle strength to thereby support motions such as walking and riding (moving between a wheelchair and a bed, and the like). This technique has also been applied to development of a wearable motion supporting device that assists heavy work of a non-handicapped person. In order to drive the wearable motion supporting device for a long time, a battery having a long life is required. The above-described battery is generally large and heavy. Consequently, wearable motion supporting devices each having a structure that does not put a load of the device including the battery and a wearing fixture on a wearer have been described in Patent Documents 1, 2.
As shown in FIG. 14A, a wearable motion assisting device described in Patent Document 1 includes a wearing fixture 101 provided with an actuator, a biological signal sensor 102 that detects a biological signal of a wearer, and a control device 103 that operates the actuator, based on the biological signal of the wearer. The wearing fixture 101 includes a waist portion 104 wrapped around a trunk of the wearer, a backpack 105 inserted into the waist portion 104 from above, and leg portions 106 fixed to legs of the wearer. In the backpack 105, a battery and the control device 103 are housed. The leg portions 106 each include a hip joint actuator 111 fixed to a lower portion of the waist portion 104, a thigh orthosis 112, a knee joint actuator 113, a lower thigh orthosis 114 and a foot frame 115, which are connected to one another in this order. Since the wearing fixture 101 has the foot frames 115 to put feet of the wearer on, loads of the backpack and the wearing fixture are all supported by the foot frames without being applied to the wearer.
In Patent Document 2, a lower extremity exoskeleton device is described. The lower extremity exoskeleton device described in FIG. 9 in Patent Document 2 includes a pelvis frame 120, a back portion frame 121 connected to an upper portion of the pelvis frame 120, and lower extremity frames 123 connected to a lower portion of the pelvis frame 120, as shown in FIG. 15. In this lower extremity exoskeleton as well, a foot frame 124 to put a foot of the wearer on is provided in each of the lower extremity frames 123.